Showing papers in "Antonie Van Leeuwenhoek International Journal of General and Molecular Microbiology in 1975"
TL;DR: Saccharomyces, the best represented genus in the Collection, showed a low incidence of killer activity and many of the killer strains are hybrids with a commonS.
Abstract: Species of 7 of the 28 yeast genera in the National Collection of Yeast Cultures exhibited killing activity againstSaccharomyces cerevisiae. The highest incidence of killer yeasts was found in the genusHansenula (12 of the 29 strains examined).Saccharomyces, the best represented genus in the Collection, showed a low incidence of killer activity and many of the killer strains are hybrids with a commonS. cerevisiae parent. The activities of culture filtrates of the 59 killer yeast isolated responded differently to pH and four types of response were recognised.
154 citations
TL;DR: The isolation and characterization of a new methanogenic bacterium,Methanobacterium arbophilicum, is described, which was found to be an autotroph and a strict anaerobe and to have a pH optimum of 7.5–8.0.
Abstract: The isolation and characterization of a new methanogenic bacterium, Methanobacterium arbophilicum, is described. Isolation from wetwood enrichment cultures, that were obtained from methane-positive trees, required a medium containing inorganic salts, vitamins, and an atmosphere consisting of an 80:20 mixture of hydrogen-carbon dioxide. Isolates of M. arbophilicum were gram-positive, non-motile short rods that occurred singly, in pairs, or chains. The organism was found to be an autotroph and a strick anaerobe, and to have a pH optimum of 7.5-8.0. The optimal temperature for growth was 30 to 37C, the maximum being 45C and the minimum about 10C. The organism had obligate growth requirements for H2 and CO2, and organic compounds greatly stimulated growth. The generation time in shake flask culture was about 17 hr in mineral salts medium and about 13 hr in complex medium. The DNA base composition was 27.5 mol % GC.
103 citations
TL;DR: Improvements of DNA are described and recommend the following improvements of DNA: single-stranded DNA, fixed on membrane filters, and stored in vacuo at 4C, can be used reliably for hybridization for up to 20 months, and rRNA membrane filter hybridization methods can be stored for 20 months without changing the hybridization results.
Abstract: We describe and recommend the following improvements of DNA:rRNA membrane filter hybridization methods. One of our aims was to avoid DNA release from filter discs during hybridization. 1. Our hybridization conditions are 2 SSC in aq. dest., with 20% formamide, 50 C, overnight for 16 hr. 2. Duplexing is over in 8-10 hr. 3. Formamide has to be very pure (O.D. less than or equal to 0.2/cm light path at 270 nm). 4. RNAase treatment: 250 mug/5 ml 2 SSC/filter at 37 C for 1 hr. 5. Our conditions for stepwise thermal denaturation are: 5 degrees C steps from 50 C to 90 C in 1.5 SSC in 20% formamide. 6. Single-stranded DNA, fixed on membrane filters, and stored in vacuo at 4C can be used reliably for hybridization for up to 20 months. 7. Concentrated DNA in 0.1 SSC, quick-frozen at -50 C and stored at -90 C for up to 2 years can be used for hybridization without much change. 8. A CsCl gradient purification step yields much purer DNA, but increases the release of DNA from filters by about 20%. Filters with 20% more DAN is a compensation. 9. rRNA can be stored for 20 months in SSC or 2 SSC at -12 C without changing the hybridization results.
102 citations
TL;DR: Measurements of the rate of lipolysis by pure cultures suggest that the organism may play an important role in the lipolytic activity of rumen contents of sheep and the demonstrated fact that the cell-free lipase excreted in the culture medium can easily be adsorbed on particulate matter in autoclaved rumen fluid may explain the absence of free lipase in clarified rumen liquor.
Abstract: Strains ofAnaerovibrio lipolytica isolated from sheep- and cow-rumen contents on a linseed oil-rumen fluid-agar medium fermented ribose, glycerol anddl-lactate. Fermentation products from glycerol were propionate and succinate, while ribose, fructose anddl-lactate were fermented mainly to acetate, propionate and carbon dioxide.
68 citations
TL;DR: The desirability is discussed of a subdivision of the genus Ceratocystis into a group characterized by the presence of a phialidic conidial state, and a group in which the conidia are usually produced exogenously.
Abstract: The desirability is discussed of a subdivision of the genusCeratocystis into a group characterized by the presence of a phialidic conidial state, and a group in which the conidia are usually produced exogenously. Corroborative evidence for this arrangement is found in the carbohydrate constitution of the cells: in all examined species of the former group (Ceratocystis s.str.) rhamnose and cellulose are absent, whereas in the latter both components are present (Ophiostoma H. et P. Sydow).
67 citations
TL;DR: The final products of hydrolysis of agarose by the endo-acting enzyme were neoagarotetraose and neoagarobiose and an apparent temperature optimum of 35C was found, due to gelling of the substrate during the assay procedure.
Abstract: Cytophaga flevensis produced an inducible agarase which was extracellular under most conditions tested. The effect of cultural conditions on the production of enzyme was studied in batch and continuous culture. In batch culture, production was optimal when Cytophaga flevensis was incubated at 20 C in a mineral medium with agar as the sole carbon source and ammonium nitrate as the nitrogen source at an initial pH of 6.6-7.0. The enzyme appeared to be subject to catabolite repression, since its synthesis was repressed when glucose was added to the medium in batch culture. Furthermore, in continuous culture, enzyme production decreased with increasing growth rate. Extracellular agarase was partially purified and the enzyme preparation obtained was very stable. The enzyme has a molecular weight of 26 000 daltons. It is a beta-agarase which is highly specific for polysaccharides containing neoagarobiose units. The final products of hydrolysis of agarose by the endo-acting enzyme were neoagarotetraose and neoagarobiose. Optimal conditions for its activity were pH 6.3 and 30C. When agarose was used as a substrate, an apparent temperature optimum of 35C was found, due to gelling of the substrate during the assay procedure.
62 citations
TL;DR: A new colorimetric method for the determination of sulphite based on its reaction with Ellman's reagent, 5,5′-dithiobis(2-nitrobenzoic acid) is described and compared for sensitivity with thep-rosaniline-HCHO method.
Abstract: The reaction of 2,4-dinitroanilinomaleimide with sulphite which has been claimed as the basis of a suitable colorimetric assay for the anion was carefully re-examined. The sulphite-imide addition product provides a suitable and specific qualitative test for sulphite after separation by paper chromatography but the method as previously used is probably measuring the hydrolysis of the imide to 2,4-dinitroanilinomaleamic acid and cannot be used for sulphite determination either colorimetrically or in kinetic assays. A new colorimetric method for the determination of sulphite based on its reaction with Ellman's reagent, 5,5′-dithiobis(2-nitrobenzoic acid) is described and compared for sensitivity with thep-rosaniline-HCHO method. Both methods were used to show the formation of sulphite as the initial product of arylsulphonate metabolism by bacteria. The failure to find sulphite in similar cultures of a third organism was attributed to the very high activities of sulphite oxidase found in extracts. The Ellman reagent was examined as the basis of an indicator medium for the detection of sulphite-excreting colonies.
52 citations
TL;DR: The DNA base compositions revealed two possible pairs of sibling species: S. elegans andS.
Abstract: DNA base compositions (GC content) of Saccharomyces species are reported and discussed. Several amendments of the four groups given by van der Walt are suggested, viz. the transfer of S. kluyveri to group 1, and of S. eupagycus, S. cidri, S. montanus, S. microellipsodes and S. florentinus to group 2. The synonomy of S. amurcae and S. cidri is suggested. The DNA base compositions revealed two possible pairs of sibling species: S. elegans and S. bailii, with a difference in GC content of 4.1%; S. dairensis and S. servazzii with a difference in GC content of ca. 3%. S. mrakii had a GC content of 47.3-48.5% the highest encountered in this genus and similar to that of Kluyveromyces thermotolerans.
46 citations
TL;DR: Aspergillus floriformis, A. pseudodeflectus, Eurotium xerophilum, andEmericella purpurea are described and illustrated as new species and the morphology of strains identified as A. versicolor is discussed.
Abstract: Aspergillus floriformis, A pseudodeflectus, Eurotium xerophilum (st con A xerophilus) and Emericella purpurea (st con A purpureus) are described and illustrated as new species In addition the morphology of strains identified as Aspergillus melleus, A caespitosus and A versicolor is discussed
36 citations
TL;DR: Characterization indicated six different types of Pseudomonas strains, one of which belonged to the genus Alcaligenes hitherto never reported to degrade oxalate, which differed physiologically from strains already known.
Abstract: Forty-one cultures degrading and assimilating oxalate were isolated from chicken dung Characterization indicated six different types One of these belonged to the genusAlcaligenes hitherto never reported to degrade oxalate Three groups ofPseudomonas strains differed physiologically from strains already known
31 citations
TL;DR: Pseudomonas oxalaticus OX1 has been grown in a mineral salts medium with oxalate or formate as the sole source of carbon and energy and the results indicated that the Haldane equation was the simplest function to describe quantitatively the kinetics of the observed substrate inhibition.
Abstract: Pseudomonas oxalaticus OX1 has been grown in a mineral salts medium with oxalate or formate as the sole source of carbon and energy. At concentrations of these substrates above 50mm inhibition of growth was indicated by a long and variable lag phase in batch culture. This inhibition was further studied by estimating maximum specific growth rates at different substrate concentrations using the extended culture technique for control of the substrate concentration. With formate, inhibition became apparent at substrate concentrations above 20mm, whereas oxalate inhibited growth at concentrations above 15mm. Complete inhibition was not observed even at concentrations of 100mm. A number of inhibition functions were fitted with the experimental data using computer analysis. The results indicated that the Haldane equation was the simplest function to describe quantitatively the kinetics of the observed substrate inhibition. Studies on the rate of oxygen uptake at different concentrations of oxalate indicated that respiration was much more sensitive to inhibition than growth. However with formate, inhibition of respiration was not observed up to concentrations of 50mm, indicating that different mechanisms may underlie the observed growth inhibition by the two substrates.
TL;DR: An experimental equipment for dry-heat inactivation of bacterial spores in an open system using Infrared (IR) radiation for energy transfer was developed and the z value was constant in the temperature range investigated.
Abstract: An experimental equipment for dry-heat inactivation of bacterial spores in an open system using Infrared (IR) radiation for energy transfer was developed. The dry-heat-inactivation kinetics forBacillus subtilis ATCC 6633 spores were studied in the temperature range of 120–180C. The z value (z=23C) was constant in the temperature range investigated. The advantages offered by using IR radiation in sterilization systems are pointed out.
TL;DR: Two cell-envelope fractions were isolated from chemotrophically grown cells of Rhodospirillum rubrum and showed distinct protein compositions, with a higher proportion of saturated fatty acids in cell-wall than in cytoplasmic-membrane fractions.
Abstract: Two cell-envelope fractions were isolated from chemotrophically grown cells ofRhodospirillum rubrum. On the basis of electron-microscopic investigations, chemical analysis, distribution of components involved in respiration, and polyacrylamide gel electrophoresis, the heavy fraction (ρ20=1.246 g per cm3) was identified as cell-wall, and the light fraction (ρ20=1.145 g per cm3) as cytoplasmic-membrane fragments. Electron micrographs showed cell-wall fragments as open structures while cytoplasmic-membrane preparations were composed of closed membrane vesicles. With respect to the main classes of chemical compounds, cell wall could be distinguished from cytoplasmic membranes by a rather low ratio of phospholipids per protein and a high ratio of carbohydrates per protein. The relative proportion of individual neutral sugars as well as phospholipids (except for lysophosphatidyl ethanolamine) revealed no significant differences between both envelope fractions. Fatty acid analysis demonstrated a higher proportion of saturated fatty acids in cell-wall than in cytoplasmic-membrane fractions. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the fractions showed distinct protein compositions. While in cell-wall preparations polypeptides of 43000 and 14000 daltons predominated, 56000- and 52000-dalton polypeptides were the main protein subunits of cytoplasmic membranes. Cross contaminations of both cell-envelope fractions were defined.
TL;DR: The agglutination factors ofa and α mating types ofSaccharomyces cerevisiae were solubilized from isolated cell-wall fractions by treatment with snail enzyme (Glusulase) and shown to be adsorbed specifically by cells of the opposite mating type, resulting in the loss of Agglutinability of these cells.
Abstract: The agglutination factors ofa and α mating types ofSaccharomyces cerevisiae were solubilized from isolated cell-wall fractions by treatment with snail enzyme (Glusulase) and shown to be adsorbed specifically by cells of the opposite mating type, resulting in the loss of agglutinability of these cells. The agglutination factors ofa and α types adsorbed by cells of the opposite mating type at pH 5.5 were eluted at pH 9.0. These factors were further purified on Sepharose 4B. From the elution pattern on Sepharose 4B, the molecular weights of the solubilized agglutination factors are estimated to be about one million. Thus purified agglutination factors contained carbohydrate and protein and were considerably resistant to heat treatment. Neutral protease ofBacillus subtilis inactivated botha and α type agglutination factors. Trypsin inactivated the α type agglutination factor only.
TL;DR: A mould which was isolated from a solution of paracetamol was identified as aPenicillium species and was found to possess the ability to utilise a series of substituted acetanilides, including par acetamol, phenacetin and metacetaml as sole carbon sources for growth.
Abstract: A mould which was isolated from a solution of paracetamol was identified as a Penicillium species and was found to possess the ability to utilise a series of substituted acetanilides, including paracetamol (4-hydroxyacetanilide), phenacetin (4-ethoxyacetanilide) and metacetamol (3-hydroxyacetanilide) as sole carbon sources for growth. Studies with washed-cell suspensions indicated that growth of the Penicillium isolate in the presence of paracetamol induced the respective enzyme systems for the degradation of this compound. Manometric studies measuring oxygen uptake rates, indicated that the mould was capable of degrading paracetamol to acetate and 4-aminophenol. Acetate was further metabolised whilst 4-aminophenol accumulated in the growth medium and was subsequently i-entified by UV spectroscopy and thin-layer chromatography. Similar experiments with phenacetin indicated metabolism by the mould to acetate and 4-ethoxyaniline which was isolated and identified by subsequent analysis of the growth medium. However, unlike 4-aminophenol and 4-ethoxyaniline, the degradation product (3-aminophenol) from metacetamol metabolism was further degraded by the mould.
TL;DR: The oxidation of hydrocarbons, alcohols, aldehydes, fatty acids, methyl ethers and sugar phosphates by methane-utilizing bacteria was studied and there was much similarity between strains within the same group.
Abstract: A number of different methane-utilizing bacteria are described and compared with isolates of other investigators. The strains can be divided into three groups based on pigmentation, cell morphology and internal membrane structures.
TL;DR: Vibrio alginolyticus strains recently isolated from Dutch coastal seawater changed flagellar organization when cultivated in the presence of certain chemical agents, induced by these agents, swarming on agar media was inhibited.
Abstract: Vibrio alginolyticus strains recently isolated from Dutch coastal seawater changed flagellar organization when cultivated in the presence of certain chemical agents. On agar media with more than 4.0% (w/v) NaCl the number of lateral flagella per cell decreased with increasing salt concentration. Both on agar media and in broth cultures with 6.0–9.0% (w/v) NaCl, cells with polar tufts of 2–4 sheathed or unsheathed flagella were frequently found. Cells grown on agar media with 7.3–9.8% (w/v) Na2SO4 had drastically reduced numbers of lateral flagella, but lacked polar tufts.
TL;DR: Results indicate that the sex-specific substance responsible for the sexual agglutination (agglutination factor) in a type cells differ from that in alpha type cells.
Abstract: Haploid Saccharomyces yeasts showed sexual agglutination when a and α type cells were mixed. Two types of a type strains were found; one constitutive and the other inducible concerning agglutinability. In α type strains, no such differentiation was observed. Agglutination was inhibited by protease treatment. Secretion from α type cells induced agglutinability in inducible a type cells. The activity of the secreted principle was heat-stable. The secretion is thought to induce de novo synthesis of proteinous sex-specific substances or to uncover preexisting sex substances.
TL;DR: Evidence is presented that proposals (a) and (b) are untenable and (c) is only partly responsible for bacterial survival and growth in the solutions, which calls attention to the presence of a factor that is antibacterial but not antifungal; namely, a high concentration of glycine.
Abstract: The most serious complication of prolonged intravenous infusion of hypertonic dextrose and amino acids is infection. Frequently, the etiology is fungal rather than bacterial. Previous authors have suggested that bacterial survival and growth in the solutions is suppressed by (a) high dextrose concentration, (b) high osmolality, or (c) low pH. This paper presents evidence that proposals (a) and (b) are untenable and (c) is only partly responsible. We call attention to the presence of a factor that is antibacterial but not antifungal; namely, a high concentration of glycine.
TL;DR: Washed cell suspensions of Hyphomicrobium spp.
Abstract: Washed cell suspensions ofHyphomicrobium spp. were able to oxidize methanol, formaldehyde and formate. This suggested that enzymes for the oxidation of these compounds were present. The pathway of the oxidation of methanol to carbon dioxide and water has been investigated using cell-free extracts. An ammonium-ion-activated, phenazine methosulphate-linked methanol dehydrogenase was detected. This enzyme has a dual substrate specificity for normal primary alcohols and formaldehyde. It has a high pH optimum for activity of 9.5. The pathway is completed by an NAD-linked formate dehydrogenase. This enzyme is inhibited by low concentrations of potassium cyanide, copper sulphate and hypophosphite.
TL;DR: A new yeast species,Bullera piricola, is described, which differs from allBullera species known at present by forming symmetrical as well as asymmetrical ballistospores.
Abstract: A new yeast species, Bullera piricola, is described. The three strains studied were all isolated from the pear phylloplane. This species differs from all Bullera species known at present by forming symmetrical as well as asymmetrical ballistospores. The problem of its integration into the genus Bullera Derx is discussed. An amended diagnosis of the genus Bullera is given.
TL;DR: The role of different fractions of rumen contents in the hydrolysis of trilinolein and the subsequent hydrogenation of the linoleic acid has been investigated by a series of in vitro incubations.
Abstract: The role of different fractions of rumen contents in the hydrolysis of trilinolein and the subsequent hydrogenation of the linoleic acid has been investigated by a series ofin vitro incubations.
TL;DR: A number of acriflavine-induced mutants ofCandida albicans, characterized by their inability to grow on acetate as a source of energy, were screened for their cytochrome absorption spectra.
Abstract: A number of acriflavine-induced mutants ofCandida albicans, characterized by their inability to grow on acetate as a source of energy, were screened for their cytochrome absorption spectra. Three mutants with different spectra, along with their parent, were selected for comparative studies, of their growth, respiratory activities and cellular structure. The spectrum of one of the mutants was the same as that of the wild-type, but the growth rate and yield of cells on glucose medium were only about 60% of the wild-type's; those of a second mutant deficient in cytochromes aa3 were 50%, and those of a third mutant deficient in cytochromes aa3 and b were less than 5% of those of the wild-type. The cytochrome-complete mutant and the wild-type showed respiratory activity both on glucose and ethanol well above the endogenous, the cytochrome aa3-deficient mutant showed only endogenous respiration, and the cytochrome aa3, b-deficient mutant no respiration at all. Electron microscopy of the wild-type cells revealed discrete, regular ovoidal, cristate mitochondria spaced near the periphery of the protoplasm; the cytochrome-complete mutant showed an abundance of large, cristate, but morphologically irregular mitochondria; the cytochrome aa3-deficient mutant had fewer but still large, cristate, somewhat irregular mitochondria; and the cytochrome aa3, b-deficient mutant only a few simple vesicles without discernible cristae.
TL;DR: Representatives of three new asporogenous species were isolated from washings of ion-exchange resin in a guanosine monophosphate manufacturing plant and the DNA base composition, proton-magnetic-resonance spectrum of extracted polysaccharides, and serological characteristics of the yeasts were investigated.
Abstract: Representatives of three new asporogenous species,Candida flavificans, Candida inositophila, andTorulopsis sorbophila were isolated from washings of ion-exchange resin in a guanosine monophosphate manufacturing plant. The DNA base composition, proton-magnetic-resonance spectrum of extracted polysaccharides, and serological characteristics of the yeasts were investigated in addition to the characteristics commonly employed. Descriptions of the new species are given.
TL;DR: The effect of inhibitors on formate oxidase activity and the other enzyme activities of the particulate formate-oxidizing fraction indicate that the oxidation of formate is linked to the respiratory chain.
Abstract: Oxalate is metabolized by the glycerate pathway involving glyoxylate carboligase in Alcaligenes LOx and Pseudomonas KOx, and by the serine pathway involving hydroxypyruvate reductase in Ps.MOx and Ps.AM1 (var. 470). Although A.LOx does not grow on formate, stimulation of growth was observed in the presence of amino acids and a few Kreb's cycle intermediates. A.LOx possesses two different mechanisms for the oxidation of formate: (1) the constitutive formate oxidase which is present in the particulate fraction of oxalate-grown and succinate-plus-formate-grown cells; (2) the inducible NAD-linked formate dehydrogenase present in the 100 000 x g supernatant fraction of the cell-free extracts of oxalate-grown cells alone. The two systems occur simultaneously in oxalate-grown cells. The effect of inhibitors on formate oxidase activity and the other enzyme activities of the particulate formate-oxidizing fraction indicate that the oxidation of formate is linked to the respiratory chain.
TL;DR: It is suggested that in addition to breaking disulphide bridges in the cell wall the thiols may also render the plasmalemma permeable to certain low-molecular-weight substances.
Abstract: Treatment of cell suspensions ofSaccharomyces fragilis with 0.01m β-mercaptoethanol or dithiothreitol released a variety of substances of high and low molecular weight. Twenty-two high-molecular-weight glycoproteins were separated by a combination of chromatography on DEAE cellulose and polyacrylamide gel electrophoresis in presence of sodium dodecylsulphate. The carbohydrate components consisted of at least 95% mannose and the protein components had threonine and serine as the major amino acids. Only very small amounts of phosphorus were associated with the high-molecular-weight components. The low-molecular-weight substances were probably released from the internal cell pool and uracil and hypoxanthine were identified as components of this fraction. It is suggested that in addition to breaking disulphide bridges in the cell wall the thiols may also render the plasmalemma permeable to certain low-molecular-weight substances. Such effects are not lethal since the yeast can be trained to grow in presence of 0.01m mercaptoethanol.
TL;DR: A description of a new yeast species from soil-Lipomyces anomalus-which differs from all the accepted Lipomyces spp.
Abstract: A description of a new yeast species from soil - Lipomyces anomalus - is given. It differs from all the accepted Lipomyces spp. by the formation of abundant pseudomycelium, absence of capsules, the assimilation properties, and its habitat: the north taiga subzone.